Epilepsy is a chronic condition produced by temporary changes in the electrical function of the brain, causing seizures, which can affect awareness, movement, or sensation.

Seizures occur when clusters of nerve cells in the brain, called neurons, signal or communicate with each other abnormally. During a seizure, the neurons' normal pattern of activity is disturbed, causing them to fire as many as 500 times per second (normal rate is about 80 times per second). This can cause strange sensations, emotions, and behavior, or convulsions, muscle spasms, and/or loss of consciousness.

Neurons in Nerve Tissue

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A diagnosis of epilepsy is usually not made until a person experiences a seizure more than once without a known cause. According to the Epilepsy Foundation, about three million Americans have epilepsy.

The causes of abnormal brain wiring and imbalance of neurotransmitters are numerous. They can include:

In many cases, the exact cause of epilepsy is not known. When a cause is not known, the disease is idiopathic.

What are the risk factors for epilepsy?
What are the symptoms of epilepsy?
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What are the treatments for epilepsy?
Are there screening tests for epilepsy?
How can I reduce my risk of epilepsy?
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What is it like to live with epilepsy?
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